Tools to fiddle with Mobitec flip-disc displays
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Lauri Võsandi 2d6428446e Initial commit 2 weeks ago
firmware Initial commit 2 weeks ago
.gitignore Initial commit 2 weeks ago
README.md Initial commit 2 weeks ago
extract-fonts.py Initial commit 2 weeks ago

README.md

Intro

Mobitec flip-disc displays use MC27C1001 EPROM-s to store the firmware (?) and fonts. In the firmware/ directory you can find two ROM dumps.

Useful commands

To extract font sections:

dd if=mobitec-1682-r7-bib-01979-r3.bin of=mobitec-1682-r7-bib-01979-r3-fonts.bin skip=64 bs=1024
dd if=mobitec-01682-r7-bib-01369-r9.bin of=mobitec-01682-r7-bib-01369-r9-fonts.bin skip=64 bs=1024

For diffing font sections:

dhex mobitec-1682-r7-bib-01979-r3-fonts.bin mobitec-01682-r7-bib-01369-r9-fonts.bin

Dump structure

The firmware seems to be located in the first 7KiB and the font data starts at 0x10000 offset.

The font beginning marker seem to consist of a character from a to z followed by at least 60 null characters. They don't seem aligned or indexed in any way so easiest is just to scan for known markers.

After the beginning marker you can find the lookup table which maps printable ASCII characters to a glyph address. The lookup table is 190 bytes (95x 16-bit addresses) which correspond to ASCII characters 32 up to 126. Not all fonts include all characters, missing glyphs are represented by address 0. Note that the glyph address is relative to the beginning of font structure, beginning marker inclusive.

At the glyph address first width and height of the glyph are found represented by two 8-bit integers. The actual bitmap data follows in 8x8 pixel tiles packed together as 8 bytes.